Extrusion Press

Routine Inspection & Maintenance Chapter 1

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Routine Press MaintenanceRoutine Press MaintenanceRoutine Press MaintenanceRoutine Press Maintenance

This Chapter Sponsored by Kennedy Eurotech Inc. www.alkennedy.com

The Need for Regular Inspection and Maintenance The common enemies of the horizontal extrusion press are gravity, friction, fatigue, dirt and foreign matter. The horizontal position requires special support surfaces to bear the weight of components throughout the operating cycle. These bearing surfaces are subject to wear from constant friction, and to damage from dirt and foreign matter that are common around the press. Heavy equipment and tooling may be dropped on these surfaces, causing permanent damage. Lubricants and hydraulic fluids catch and hold dirt onto the critical surfaces. Proper alignment of the press is critical to minimizing wear, and also to minimizing stresses on the press structure and components. Although press components may be oversized for long life, a seemingly minor misalignment may multiply the stresses involved and result in premature failure. For example, misalignment of the main crosshead may result in excessive wear to the main ram, main cylinder packing, and main cylinder bushing; and to the crosshead cylinders, bushings, and packings. The crosshead cylinder rods may fail due to fatigue loading. Alignment of the stem, container and tooling stack with the press platen and pressure ring are likewise critical to extrusion tolerances as well as to the life of the container lining, container shift cylinders, and die carriers. Operating with badly worn container guides makes proper alignment impossible and eventually results in excessive costs for poor quality, downtime and repair costs. The guide ways and shoes for the container and crosshead must be protected from dirt and foreign matter as well as misalignment. Dirt is easily air-blown or tracked on the shoes of workers. Careless handling of heavy tooling, bars, or hand tools can cause a permanent nick or dent to these surfaces. The same is true for the main ram and for crosshead or container cylinder rods. Effective maintenance must begin with educating all workers about these hazards and their consequences, as well as proper preventive measures. Minor damage must be recognized by inspection and corrected before secondary damage results.

Scheduled Maintenance Planned maintenance of equipment on a regular basis allows for the most efficient use of

both workers and machine. With scheduled downtime, work can be performed when all the necessary skills, parts, supplies, and test equipment are available. Production workers may be scheduled off or assigned to other duties. Many different tasks may be carried out at the same time. Work may be performed more carefully. By recording historical wear rates, certain components may be replaced before unplanned breakdowns occur.

The Voice of Experience: One old-timer with many years experience in press maintenance offered this advice before he retired: Think of the press as a small child who isnt yet able to talk. So we must care for him gently, and listen to him to understand even the smallest problem. We should clean him constantly and carefully, and take care of even the smallest leakage. In return for this, we will be pleased with his performance.


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By contrast, breakdown maintenance must depend on the workers and skills available at the moment of breakdown, and delays often occur while the appropriate people, repair parts, and supplies are rounded up. Work is seldom performed well or efficiently, and many items that could have been done at the same time must be delayed until the next unplanned breakdown. Well-organized plants schedule press repairs on a regular frequency, usually taking PM (preventive maintenance) or down-days weekly or semi-weekly. Tasks are scheduled according to items noted on daily inspections, plus items scheduled at a frequency determined from past experience. Monthly, quarterly, semi-annual, and annual PM periods will take longer according to the additional checks included in the established schedules. It is not possible to set an overall standard frequency for preventive maintenance; it is different for each press and for each company. Even though suggested maintenance intervals are given in Chapter A - Maintenance Schedules, these are indicative only and should be adjusted based on your actual situation:

the design of your equipment

its age its actual history requirements of your

production schedule The frequencies suggested here are based on the opinions of various equipment suppliers and experienced extrusion plant engineers, and they can be a good reference for establishing your own schedules and program.

Predictive Maintenance Predictive maintenance uses modern technology to determine a machines condition while it is operating, records the information, and analyzes the recorded information to predict the optimum time and extent of repair needed to keep the machine in its best condition.1 Examples of Predictive Maintenance of Extrusion Presses include:

1 Eidson, B., Improving Equipment Effectiveness Through Total Productive Manufacturing,

Proceedings of 6th International Aluminum Extrusion Technology Seminar, (1996).

Figure 1-1: Ultrasound test of main cylinder (Photo courtesy of Presezzi Extrusion)

Figure 1-2: Infrared view of an overheated fuse block

Your ad will appear here with illustrations, text, and link to your

web site. Example:

www.ET12.org


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hydraulic oil analysis Magnetic Particle Inspection and Ultrasonic Testing of press components to detect

fatigue cracks infrared scans of electrical equipment to look for overheating vibration monitoring

Preventive Maintenance Preventive Maintenance (PM) describes any scheduled maintenance task which is

performed to prevent unplanned maintenance or breakdown. PM usually involves routine, repetitive tasks, and may be performed by maintenance people or operators. The list of PM tasks for any plant is constantly changing, according to records of breakdown-causing problems as well as items found on other PMs. Included in Chapter A are suggested Maintenance Schedules for extrusion press plants. These can be used as the basis for establishing a PM program if one does not already exist. (Copies of these schedule sheets are also included in Spreadsheet format on the CD version of this Manual.) Preventive Maintenance Planning After the Preventive Maintenance program is in place, effective performance requires planning for each PM. This means devoting the time and manpower to analyze each task and its frequency; then identifying the personnel, tools, parts, supplies, and test equipment needed for each task; and, finally, assuring that all are available for the PM period. Without this kind of planning, some tasks will be left incomplete or skipped entirely, and the PM program will be a failure. Daily Walk-Around Inspection. There is no substitute for a daily operating check of the press, just as an airplane pilot or truck driver makes a routine walk around check of his equipment. Without stopping the press, an appropriately trained supervisor, maintenance person or operator should check the press thoroughly, noting items which may safely observed while the press is operating. The items observed will then be scheduled for repair according to the urgency of the problems. A suggested check list for this daily inspection is included in the Preventive Maintenance Schedule. In general: Look at the motions of the main moving parts: container, crosshead, die changer, butt shear. Are

movements generally smooth and parallel? Look at alignment on a discard butt (or special scribed-dummy-die butt): a quick inspection will

indicate alignment and condition of the container. Look at the tooling carrier or die slide: wear or build-up which may result in premature wear will

be evident here. Is the die changer or carrier clean? Look at the container, ram stem, and fixed dummy block: signs of buildup, misalignment, bent

ram, or other problems will appear here. Look at the main ram and auxiliary cylinders: oil leaks or damage to rods or bushings may be

spotted. Look over the hydraulic system: for leaks, vibration, low oil, excess heat, changes in oil

temperature, or change in oil condition; all are signs of trouble ahead. Look for changes: whats different from yesterday, and why? Note: also see the check-sheet-based approach by David Turnipseed in The Voice of Experience, page 1-8.

Mechanical Maintenance Main Cylinder and Packing. The main cylinder packing should be observed for oil leaks, in particular for any sudden increase in leakage, which may indicate damage to the packing or main ram surface. Packing should be checked for embedded particles, which may score the surface of


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the main ram. When tightening the packing, the gland ring must be tightened evenly all around. Spacers made of keystock may be used to measure that it is being tightened uniformly. Periodically the main cylinder should be checked for possible excess wear to the main cylinder bushing, as follows: extend the main ram just far enough to accommodate a machinists level on the ram surface (about 18). At this point the main ram should be fully supported by the main ram bearing bushing. The main ram should be level to the same tolerance as the main cylinder: 0.0005 in/ft (0.04 mm/meter). If the main cylinders platen surface is perpendicular and the ram is not level, the main ram bearing bushing is likely worn and may require replacement. The guide shoes of the moveable crosshead should just be touching the guide ways in this position. Main Ram. The main ram must be checked for nicks or scratches, which will damage packing and increase oil leakage. If nicks or scratches occur, the surface must be immediately polished smooth with a stone, then washed to remove the residue. Follow up carefully -- watch the area closely and repack as soon as convenient, or immediately if scoring persists. Tie Rods. Check prestress of the tie-rods by feeling for clearance between the inside nuts and flanges while the press is under load. Any clearance, even 0.001 inch (0.025 mm) indicates loss of prestress. Each nut should also be match-marked to the platen so that any rotation of the nut will be apparent. Follow the press manufacturers instructions for loosening nuts and adjusting the prestress of tie rods. In the absence of such manufacturers instructions, the following general procedure may be useful: Prestressing of tie rods is usually accomplished by raising the press tonnage to 10% above the rating and using the main ram to stretch the rods, then tightening the inside nuts and locking them to retain the prestress. The inside nuts should remain tight, even under full load, and should not allow insertion of even a 0.001 inch feeler gauge (0.025 mm) between the nut and flange. Likewise when the load is relaxed there must be no clearance between the platen and outside nuts. With sleeved tie-rods, no space is permitted between the sleeve and platen. Any such space indicates a loss of pre-stress and requires re-torqueing of nuts and rechecking of squareness. Note also the recommended procedures for detecting, monitoring, and repairing cracked tie rods, in Chapter 4 - Inspecting and Repairing Major Components. Front Platen. The condition of the front platen pressure ring is critical to die performance and so should be checked often with straightedge and feeler gauge. The primary concerns are looseness, cracking, or distortion; for example coining, in which a permanent impression is made in the ring. Repair or replace the pressure ring if any damage is detected. The old ring may sometimes be returned to a smooth and parallel condition by grinding and shimming. Crosshead, Guideways, and Guide Shoes. Correct adjustment of the crosshead is discussed in Chapter 2- Press Alignment. In addition to alignment, the guide ways must be checked for nicks or other damage to the surfaces, for example damage due to dropped tooling. Another concern is brass pick-up on the ways, indicating possible poor lubrication, or that the brass shoes are not making proper contact due to misalignment. Guide shoes should be removed and fully inspected periodically; replace or re-machine as needed. Many presses are fitted with wipers to remove dirt and foreign matter ahead of the shoes; check these wipers for proper alignment. Crosshead Cylinders. Check for excessive oil on the rods, which may indicate damage to packing or bushings. Check clearances around the rods (also when repacking) which may indicate excess wear of bushings. Check for nicks, bending, or other damage to rods, which may damage the packing. Check for oil leaks at cylinder connections. Check that the attachment nuts to the crosshead are tight, including while under load. Check for excess heat, which may indicate that oil is by-passing the piston head (cylinder rebuild needed); hold the crosshead against main cylinder at full pressure and check for temperature rise. Ram Stem. In addition to the alignment checks indicated in Chapter 2 - Press Alignment, the ram stem should be checked often for signs of bending, cracks, or upset, due to its critical nature and to the excessive stresses involved. Check its straightness with a straightedge. Check the pressure plate to which the stem is mounted for damage, deflection, or coining, using a straightedge and


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feeler gauges; remove and re-grind flat if damaged. The seat must also be clean. The stem retention ring or other stem mounting devices must be properly tightened. Check the stem and fixed dummy block often for signs of build-up or excessive wear. Any contact forces are transmitted back to the main cylinder and may result in premature wear of the main ram and bushings, and to the crosshead cylinders as well. Container Holder, Guides, and Guide Shoes. Correct adjustment of the container is discussed in Chapter 2 - Press Alignment. In addition to alignment, the guide ways must be checked for nicks or other damage to the surfaces, for example damage due to dropped tooling. Another concern is brass pick-up on the ways, indicating that the brass shoes are not making proper contact due to misalignment. Guide shoes should be removed and fully inspected periodically; replace or re-machine as needed. Many presses are fitted with wipers to remove dirt and foreign matter ahead of the shoes; check these wipers for proper alignment. Check the condition and tightness of container keys, lock rings, and/or retainer bolts, according to the design of the container holder. Check for signs of relative movement between the container and holder, which may indicate inadequate keying and locking, or possible structural cracks or wear. Re-machining or replacement may be necessary.

Container Cylinders. Check for excessive oil on the rods, which may indicate damage to packing or bushings. Check clearances around the rods (also when repacking) which may indicate excess wear of bushings. Check for nicks, bending, or other damage to rods, which may damage the packing. Check for oil leaks at cylinder connections. Check that the attachment nuts to the container are tight, including while under load. Check for excess heat, which may indicate that oil is by-passing the piston head; hold the container against the die stack at full pressure and check for temperature rise. Butt Shear. Correct adjustment of the butt shear with the tooling stack is discussed in Chapter 2 - Press Alignment. Check for wear in the blade guides, which may allow the blade to deflect away from the die stack. Check the condition of the blade; repair or replace as needed. Nicks and other

Figure 1-3: Illustration of press components (Drawing courtesy of RL Best)


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blade damage may indicate misalignment or poor condition of the tooling stack. The die stack must be completely uniform in overall dimensions; variations in excess of 0.020 (0.5 mm) are likely to cause damage to the butt shear blade. A plant standard for overall tooling dimensions should be maintained for each press and rigidly followed to avoid problems; non-standard tooling must be modified or discarded. Different designs and devices are available to insure correct positioning of the die stack. Cylinder-operated lever clamps are often devised to hold the die stack securely during shearing. Also, the condition of the die carrier or die changer pocket must be inspected often to maintain keys and critical dimensions in the proper condition. Build-up of aluminum or dirt will also increase the risk of misaligned tooling. The hydraulic shear cylinder should be maintained as follows: Check for excessive oil on the rod, which may indicate damage to packing or bushings. Check for nicks, bending, or other damage to the rod, which may damage packing. Check for oil leaks at cylinder connections. Check that the attachment nuts to the shear blade are tight. Check for excess heat, which may indicate that oil is by-passing the piston head. Check for excess play in blade guides (depending on the design), which may allow unusual strain on the cylinder. Note that improved butt shear designs are available for retro-fit to older presses. (See Chapter C - Modernizing Older Presses.) One important feature is addition of a butt knocker, which in some cases may be retrofitted without a new butt shear. It is usually a cylinder-actuated device which sweeps the shear area after every stroke to insure separation of the butt. Another way to insure good separation of sheared butts is the automatic application of high-tech, high temperature lubricants/parting compounds to the shear blade. A spray is actuated automatically, for example after each five billets (see page 1-7). Die Changer. Correct adjustment of the die stack and die changer is discussed in Chapter 2 - Press Alignment. Check all bolts and nuts for tightness. Check brass guide ways for wear or scoring; look for looseness of the die slide or carrier in the guides. Check critical die pocket dimensions for wear or build-up; restore correct dimensions as needed before problems arise with the butt shear or press alignment. Check for signs of relative movement between tooling and holder during shearing, which may require tightening, or build-up and re-machining. Check the die changer hydraulic cylinder(s) as follows: Check for excessive oil on the rod, which may indicate damage to packing or bushings. Check for nicks, bending, or other damage to the rod, which may damage packing. Check for oil leaks at cylinder connections. Check that the attachment nuts to the changer or carrier are tight. Check for excess heat, which may indicate that oil is by-passing the piston head. Check for excess play in die changer guides (depending on the design), which may allow unusual strain on the cylinder(s). Check for wear or scoring where the die changer passes along the front platen. If there is scoring due to contact, grind the area smooth and lubricate it; adjust or shim the slides or gibs to eliminate the contact. Billet Loader. Work on the billet loader is one of the most dangerous areas of press maintenance. Special jigs or fixtures are needed to block up the loader in a safe working position and guard against its falling. Lock-out/tag-out procedures are especially critical when working on the billet loader. Correct adjustment of the billet loader is indicated in Chapter 2 - Press Alignment. Check the loader for loose bolts and nuts. Check all pivot points for excessive play or wear; replace bushings as needed. Check the loader for structural damage due to collisions. (Many presses require stocking of a complete spare loader due to frequent collisions.) Check the billet loader hydraulic cylinder(s) as follows: Check for excessive oil on the rod, which may indicate damage to packing or bushings. Check for nicks, bending, or other damage to the rod, which may damage packing. Check for oil leaks at cylinder connections. Check that the attachment nuts to the loader are tight. Check for excess heat, which may indicate that oil is by-passing the piston head. Check for excess play in the pivots, which may allow unusual strain on the cylinder(s). On presses which still use loose dummy blocks, condition of the blocks and their match-up with the ram stem should also be checked. Alignment must be made with a dummy block in place.


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Lubrication General Press Lubrication. Lubrication of extrusion press components is generally not a complicated issue. The presence of oil mist, hydraulic leaks, and sprayed tooling lubricants usually result in a general oil film over the entire press area. It is more important to insure that dirt and foreign matter are not trapped on sensitive surfaces by this oil film. The location and type of press lubrication points depends on the design of the press. The press manufacturers original recommendations should be followed. Where the original lubrication instructions have been lost over the years, past practices are usually a sufficient guide. Routine lubrication maintenance consists of greasing all required locations, usually daily; and filling combination-type oiler units. High-Temperature Lubrication for Press Tooling. Advancing technology has resulted in development of several new families of engineered lubricants and parting compounds which are useful for specific press applications: Billet/Dummy Block Lubricants. The ends of pre-cut billets have traditionally been lubricated by painting with graphite dispersions, in a base of either kerosine or water. However, increasing use of fixed dummy blocks, combined with hot-sheared billets, has forced the development of automatically applied alternatives, for example after the billet is sheared. Presenty there are two popular methods of applying lubricant to the surface between billet and dummy block:

Automatic spraying of the dummy block with proprietary liquid parting compounds. An automatic applicator descends from above by means of a pneumatic cylinder to align with the dummy block during the press dead cycle; then a rotating nozzle applies lubricant to the face and edges of the dummy block. PLC or relay controls determine the frequency and duration of application, followed by a short air purge. Typically, the block is sprayed every 5 to 10 billets. The fluids applied are specially developed to facilitate separation and prevent aluminum build-up, without accumulation of chemicals on the die or tooling. Typical supplier: Amcol Corporation, Hazel Park, Michigan (Telephone 248-414-5700).

Flame application of carbon (soot) to the billet face. The billet is paused at some point of its transfer to the press, while a carbon-rich flame applies a coating of soot to the billet end. An acetylene or Mapp-gas flame burns for 3 to 4 seconds with a visibly black smoke. (The air pollution aspect is a problem in some plants.) Typically, every billet is coated. Equipment source: most suppliers of hot billet shears offer an acetylene lubricator.

Electrostatic application of Boron Nitride (BN) powder to the billet and/or other tooling surfaces. BN powders are expensive and so must be applied carefully to minimize cost, so application is normally by electrostatic sprayer. Controls may be set to permit spraying intermittently for example, every 3 to 5 billets. Typical suppliers: o Castool, Scarborough, Ontario, www.castool.com, (Telephone 416.297.1521) o Amcol Corporation, Hazel Park, Michigan, www.amcolcorp.com (Telephone

248.414.5700). Butt Shear Lubricants. Fixed nozzles are positioned to apply lubricant to the edge of the shear blade, typically after every 5 to 10 billets. Control is automatic by means of a PLC or relay logic. Proprietary fluids are used. Typical supplier: Amcol Corporation, Hazel Park, Michigan (Telephone 248-414-5700). Sawing Coolants/Lubricants. Aluminum sawing, whether hot sawing at the press, or cold sawing of profiles or billets, may be significantly improved by means of advanced coolant-lubricants developed at Boeing Aircraft Co. in years past. The surface-wetting and heat removal properties of these fluids allow a significant reduction in the quantity of lubricant needed, so there is less fluid left on the product being sawed. Blade life is dramatically improved, and the quality of cut is much better. A special low-volume applicator is required due to the small quantity used. Typical supplier: Amcol Corporation, Hazel Park, Michigan (Telephone 248-414-5700), www.amcolcorp.com.


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Editors Note: One goal of the Extrusion Press Maintenance Manual is to share the valuable know-how of experienced maintenance people. On the following pages we present expert advice that comes from many years of hands-on service. The first article concerns Daily Check Sheets and Preventive Maintenance procedures. While developed for a particular press, it is useful as a basis for developing your own check sheets. It is provided by David Turnipseed, a second-generation Maintenance Manager with experience in different plants and different companies.

The Voice of ExperienceThe Voice of ExperienceThe Voice of ExperienceThe Voice of Experience

Extrusion Plant Preventative Maintenance (PM) Program Recommendations

The following is a guideline that can be applied to any equipment in the manufacturing facility but has some examples that focus on the extrusion plant in the sample check list supplied. The guideline is written with the emphasis on a production environment operating 24/7 with one 8 to 12 hour shift per month of scheduled down time for the planned Preventative Maintenance (PM) tasks. The Preventative Maintenance program is only one of the required components that are necessary to reach a high and sustainable Service Factor, but is one of the most important parts of a good maintenance program. Every manufacturing facility has to tailor their own program around their own equipment, personnel, and operating environment. This type of PM program will build better employees and at the same time make the manufacturing facility more prosperous if implemented and maintained. The PM program consists of:

I. Equipment Daily and Weekly Check Sheets II. Equipment Monthly PM Task List III. Equipment Semi-Annual PM Task List IV. Equipment Yearly Major Maintenance Task List

I. Maintenance Daily Check Sheets The Daily Check Sheets contain simple checks that are designed to have someone from the maintenance department do a brief scan around the equipment every day while the equipment is in operation. Any assignments listed that are to be carried out while the equipment in operation should be identified and approval granted by a qualified member of management that the inspections can be done safely. The inspection task should have the following objectives:

a) Safety In every manufacturing plant, safety has to be the number one concern at all times. No unsafe situation should lie in wait for days or weeks without being noticed. It is most important that any unsafe item such as a missing guard, exposed wires, loose components, etc., be spotted during this inspection so the equipment can be shut down immediately and corrected.

b) Problem Identification - One of the main objectives of the check sheets is to get the employees eyes and ears into the different areas to spot any difference in the process from day to day. Once they are in the area, everyday minor or abnormal sights and sounds within the process equipment will become obvious. The items that are listed on the daily check sheet should strategically be picked based on how critical the component or area is to the process and to make sure all areas that can be covered safely are observed. Many existing and potential problems can be identified this way. One of the key components in achieving a good Service Factor is spotting problems that could possibly turn into breakdowns.

c) Problem Correction During the daily inspection minor problems can be noticed and corrected if possible during planed times of the shift. This can eliminate extended downtime


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and prevent major problems. Much of the total downtime for the month can be attributed to minor stoppages that at the time are not major problems but are major contributors to the total downtime.

d) Problem Documentation Some problems that are found during the daily inspection are not deemed practical to correct at the moment but should be documented to have a record of the need to be taken care of during the monthly PM; or if possible the Maintenance and Production departments may plan and schedule minor problems to be corrected during breaks, meeting times, etc. The main objective is to make sure a problem, potential problem, or situation is documented for future correction.

e) Experience The daily check sheets should be done by different employees on different shifts for a time and then rotated for different processes. This will expose more people to the various processes in the plant and reduce the dependence on any one individual. Cross training should come naturally if these procedures are allowed.

f) Communication One of the main contributors to excessive downtime is communication, or the lack of it, between the maintenance technician and the production operators. The machine operator is one of the most valuable tools the maintenance department has if used correctly. There must be respectful dialog between these two every day to achieve success.

II. Maintenance Weekly Check Sheets The Weekly Check Sheets contain items that are not as critical and would require excess time if they were on the Daily Check Sheets. These items should be picked based on the severity of the outcome if there is a failure, available spare parts, time required for change out, etc., and even though they may not be checked every day, they do not need to go an entire month before they are checked. All the same objectives as the daily checks should apply, only the frequency is changed. III. Monthly Preventative Maintenance Task List The Monthly PM task list should be designed for duties that generally require planned down time. All tasks that are performed during this time should be items that have been identified as critical areas of the process, that require attention every month, and can not normally be accessed during production time. These tasks should have the following types of work:

a) Calibration Calibration of sensors and instrumentation today is an important task. Measurement sensors should be checked for integrity and validated for accuracy. The operation of system sensors is responsible for making the processes consistently reliable in all areas including safety, productivity, recovery, information and control parameters. In this information age many decisions are made based on trust in the field devices. It is very important to put together a good calibration PM program for the electrical technicians to carry out.

b) Inspection Identify critical areas of the equipment that require disassembly so that they can be done during the planned down time. The objective is to identify and repair or replace components that could possibly fail before the next PM day. Even if no work has to be performed, for many of these items their condition should be documented in order to build history so that more is learned about the life or patterns of how the components hold up.

c) Alignment All equipment failures have a root cause. Many times this root cause is loose or misaligned parts. All areas of a process that operate under critical alignment specifications should be identified and procedures written to carry out these task at this time. Attention that is given to this task will guarantee fewer failures. Examples of areas of alignment are motor/pump combinations, moving assemblies, mounted switches and sensors, cameras, etc.

d) Cleaning There are always areas of a process that can drastically be influenced by contamination. This can affect the operational life of components, accuracy, and consistency of components as well as the product being produced. Contamination is another major contributor to downtime that is often ignored. It is important that this be taken seriously in order to have a successful operation. Most problems in a hydraulic system are due to contamination.


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e) Component Replacement Components that have been identified to be changed out due to hours of operation or indicators showing near or at replacement should be replaced during the PM. Many companies use good tracking methods by computer or paper and can predict very well the life of a component. At times it can be more economical to replace a component during this time rather than incur an unplanned breakdown.

III.) Semi-Annual PM Task List The Semi-Annual PM task should be items that are identified as jobs that require more time that has been allotted for the monthly PM. Some tasks may include:

a) Special Projects Special planned enhancements that can boost productivity and recovery and show a good payback for the rest of the year.

b) Component Replacement Some processes may contain components that require replacement before the end of the year.

IV.) Yearly Major Maintenance Task The yearly major maintenance tasks should include items reserved for a low production time of the year and planned-for tasks that are not emergency items, but take more than one day to complete. However, there are some tasks that may take longer to complete but cant be postponed until the yearly shut down as there would be a risk of more lost production time waiting for this date to arrive. Examples of yearly maintenance jobs:

a) Wear and Tear Items Certain wear and tear items can last a year or years before replacement. These tasks need to be identified and planned for replacement at this time.

b) Special Projects New equipment, equipment upgrades and enhancements c) Equipment Rebuilds Complete refurbishment for better reliability throughout the year. d) Major Component Replacement For some components it is more economical to replace

before a failure occurs, but it takes more than a day for replacement.

Conclusion As can be observed from the detailed information above the Daily Check Sheets are probably the quickest to do but are the most important component of the entire PM process. Most of the daily inspection is used for planning the PM duties and tasks. Most of the small problems that are found and repaired during the daily inspections allow the allotted time of the monthly PM to be used for planned tasks. Once the monthly PM begins and the equipment is shut down and turned over to the maintenance department there is no time for planning or for looking for potential problems that should and could have been accessed during the weekly inspections. Every minute of the monthly PM time is valuable and must be productive. All planning of tasks, employee work schedules, necessary parts, outside resources and services must be accounted for. The objective is to check and certify that the processes are in favorable condition to operate for the next month with a very low probability of failure. The PM time is usually shared between general repair items, special requests and any unplanned problems that are found while working. As the program is developed more and more and the program is continually improved there should be more flexibility to shift blocks of time to different job duties. If used correctly, most of the planned downtime can be made up through a decreased amount of unplanned downtime. Other components that are required to produce a successful maintenance program are:

continuous training programs good organization of critical spare parts necessary tools for the job good relationships with the rest of the work force and (an absolute) the support from upper management.

The following pages show a few examples of the first part of the program, the Maintenance Daily Check Sheet for the maintenance technician. It is not focused on a craft (mechanical or electrical, for example) of the employee, but rather attention to a situation that could arise or a faulty part of the process that needs to be communicated and documented. The example is a Maintenance


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Daily Check Sheet for a SMS Sutton 1800 UST direct extrusion press. The monthly, semi-annually and major maintenance task lists are more geared to the craft of the technician since they focus on actual job duties. Each part of the program has to be tailored to fit the specific process and its own details. It is also important for the operators to have ownership in the program for the entire program to be successful. Check sheets and PM task should be created through a team effort that focuses on items in which the operators and maintenance technicians have a part. Following the Maintenance Daily Check Sheet on page 1-15 is the Extrusion Press Troubleshooting Chart, which explains in more detail the points on the Check Sheet and what action should be taken to resolve each type of problem.

Maintenance Daily Check Sheet Procedure 1.0 Check butt shear for proper cutting.

Check to make sure butt is being cut from die face and not torn away. If tearing occurs, refer to Sec. 1.0 on Extrusion Press Troubleshooting Chart. 2.0 Check butt knocker for proper operation.

The butt knocker rod is controlled by a pneumatic cylinder. It should stroke and strike the butt at the end of the shear stroke cycle with high impact and knock the butt away from the butt shear blade. If there is no butt stuck on the blade to absorb the high impact of the knocker rod collar, there is a spring to absorb the load. If a loud clanging noise is heard, the air cylinder mount or coupling could be loose. Refer to Sec. 1.0 on Extrusion Press Troubleshooting Chart for further information. 3.0 Monitor the press cycle. During the press cycle, watch and listen for: Closing of Container The container should advanced toward the die without shifting side to side, then slow down just before reaching the die and gently seal flat against the die ring. If there is side motion of the container housing while opening or closing or if the container is slamming into the die, refer to Sec. 2.0 on the Extrusion Press Troubleshooting Chart. Loader Cycle Once the container is closed, the loader should raise quickly, with a smooth motion and no bounce at the end of the stroke, to accept the billet from the overhead loader. If loader motion is slow or jerky, refer to Sec. 3.0 on the Extrusion Press Troubleshooting Chart. Ram Advance After the overhead loader has safely cleared from possible interference of the crosshead the main ram should advance rapidly, pushing the billet concentrically into the container without dragging on the side of the container opening. If slow movement of the main ram occurs, refer to Sec. 4.0 on the Extrusion Press Troubleshooting Chart. Dummy Block Entry - Dummy block should enter the container without any top, bottom or side load on the block. If the ram stem is forced down while entering the container or build up of aluminum on the side of the opening of the container occurs refer to Sec. 4.0 on the Extrusion Press Troubleshooting Chart. Upset/Burp Cycle Main ram should press billet against die, not slam it, into the die, and build pressure. Once the preset upset pressure is reached, the container should open enough to break the seal between the container and die, pushing the ram back with the upset billet and releasing the trapped air in the front of the container. After opening, the container should close and re-seal without slamming. If the container does not open enough to break the seal, the air will not escape and blisters will result. If the container opens more than needed, lost time will result. Refer to Sec. 2.0 on the Extrusion Press Troubleshooting Chart. Extrusion The press should build required pressure and reach a steady set point speed. The extrusion press is designed for the system to develop a maximum of 3000 PSI of hydraulic pressure on the main ram and side cylinders if required by the load and to reach approximately 44 inches per minute of ram speed. If maximum pressure of 3000 PSI can not be achieved with the main ram dead headed, refer to the troubleshooting chart. If the maximum ram speed can not be reached or the speed is fluctuating refer to Sec. 5.0 on the Extrusion Press Troubleshooting Chart.


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End of Extrusion Upon reaching a desired runout length or butt set point the press should stop extruding and decompress the pressure without excessive hydraulic shock. If extreme shock is heard or if there is a loud noise around the pre-fill valve, Refer to Sec. 5.0 on the Extrusion Press Troubleshooting Chart. Container Strip After decompression the container should start to open while the dummy block is held against the remaining length of billet to strip the expanded butt away from the container wall. There must be a delay between the container open and the ram return to prevent pulling the butt away from the die face. If both the main ram and the container move at exactly the same time, Refer to Sec. 4.0 on the Extrusion Press Troubleshooting Chart. Container Open/Ram Return After the container has reached the butt stripped position the ram will return at the same time the container opens. The dummy block should pass through the container without excessive resistance due to buildup inside the container or around the land of the dummy block. The ram should return to the home position and gently coast to a stop avoiding contact between the back of the main ram cylinder and the housing. If slamming occurs, Refer to Sec. 4.0 on the Extrusion Press Troubleshooting Chart. Butt Shear Cycle Once the dummy block and container are behind the safe-for-shearing point, the butt shear should advance downward shearing the butt clean from the die face until reaching the end of the stroke of the shear cylinder. At the end of shear travel, the pneumatic controlled butt knocker should advance and strike the butt at high impact, dislodging the remaining discard section. As the butt knocker is in operation, the butt shear cylinder should retract and travel to the top (home) position. There should be a small delay when the shear cylinder reaches the down position before returning to prevent hydraulic shock in the system. Once the shear is in the top (retracted) position, the pressure from the main pump(s) is removed and the shear is held in the up position by pilot pressure, preventing the shear assembly from drifting down if there is leakage (internal or external) on the rod side of the cylinder. If there are problems with the operation, Refer to Sec. 1.0 on the Extrusion Press Troubleshooting Chart. 4.0 Grease container, press ways, and die slide.

The container housing and crosshead are designed to slide on precision flat hardened steel ways. The load is supported on bronze wear plates (shoes) machined with grease ports to distribute the lubricant across the width of the sliding surface. The grease has to be pumped in manually through grease fittings. If the grease is properly flowing through the channels, the load will be sliding on a thin layer of lubricant. The wipers mounted on each end of the crosshead and container shoes push away any debris on the ways to prevent contamination from entering in between the bronze and hardened steel causing premature wear of the steel ways. The grease should be applied every day.

The die carriers and the drive assembly slide on a bronze wear plate that should be lubricated every day. There are grease lines mounted on the front of the platen to safely apply the grease to the sliding surface. Always use recommended lubricants. 5.0 Check hydraulic oil temperature and record. Check the press hydraulic oil reservoir temperature and record the reading on the check sheet. The hydraulic oil recommended for this system by the original equipment manufacturer is an ISO 68 and should be run at 100 degrees F to obtain a viscosity of 300 SUS for proper lubrication and system efficiency. If the oil is at a lower temperature the viscosity (resistance to flow) is increased and the system has to work harder and a noticeable slow down of movements of the cylinders and shifting of the valves will result. If the oil becomes too hot, the pumps, seals and the oil itself have limits and damage can result. If the temperature reaches 120 degrees F, start looking for possible heat generation within the hydraulic system or a decrease of heat removal from the cooling source and refer to Sec. 9.0 on the Extrusion Press Troubleshooting Chart. 6.0 Check dummy block/ram stem for excessive aluminum build up. The fixed dummy block is designed to run in the center of the container while expanding very close to the container wall, preventing blow-by or back extruding. Depending on the design of the fixed block, there should be a certain amount of float to compensate for slight variances in misalignment. If there is too much misalignment between the container and fixed dummy block, excessive build up around the land of the block and on the ram stem can occur. The result can be damage to the dummy block as well as the inner wall of the container liner. The fixed dummy block


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is generally designed with outside diameter of .035 to .045 in. below the container bore. The geometry is such that the block should expand under pressure to very close to the container wall ID while extruding and collapse back to the designed OD after the pressure has relieved, allowing the dummy block to return through the container without resistance. Over time, the steel of the dummy block can become fatigued and will not collapse, thereby dragging the aluminum that is stuck on the container walls back through. If there is excessive resistance on the main ram while returning through the container, Refer to Sec. 4.0 on the Extrusion Press Troubleshooting Chart. 7.0 Check for any high volume or high pressure oil leaks.

Check hydraulic cylinders (main ram, pull back, butt shear, die slide and shifting) for leaking oil at the rod gland packing. There should only be a minimum layer of oil on the cylinder rod for proper lubrication. Check oil lines for leaks at fittings and check for small cracks in the oil pipes. If leaks are found that are excessive, shut down the press as soon as possible and lockout and repair. For small leaks, tag the device that is leaking and prepare to fix it at the next scheduled PM. 8.0 Check container for proper sealing operation. The main pumps will drive the container closed. Upon engaging the die ring, the container closed limit switch should make, allowing the sealing pump to pressurize the container shifting cylinders on the rod end and form a tight seal between the container liner face and the die ring. If there is heavy build up on the face of the liner or the die, this may result in an insufficient seal and extrusion between the liner and die can occur (flare outs). This area can see the same pressures as the die face, and the aluminum will flow through the path of least resistance. If excessive build up occurs in one area (mainly on the bottom due to bad shearing) the container will tilt forward while sealing. This press is designed with the loader attached to the container, so if the container tilts, the loader will raise substantially causing interference between the loader cradle and the fixed dummy block. The container shifting cylinders will attempt to pull the container flat against the die ring. If the housing is low in the back (ram side) the container will tilt forward raising the loader also. If the container is high in the back, the result will be excessive pressure on the die carrier guides resulting in damage to the wear plates. When the container is sealing, look for any of these conditions. Refer to Sec. 2.0 on the Extrusion Press Troubleshooting Chart. 9.0 Check die hold down bar for damage or looseness. The hold down bar is designed to prevent the die stack tooling from being lifted during the operation of the butt shear cycle on the up or return stroke. Check to make sure there is not enough clearance between the top of the tooling and the die hold down bar for the tooling to be picked up more than the height of the key stock at the bottom of the tooling. Also, make sure there is enough clearance for the top of the tooling to traverse back and forth on the die slide without interfering with the hold down bar. If the die appears to be lifting or rotating, Refer to Sec. 1.0 on the Extrusion Press Troubleshooting Chart. 10.0 Check with the operator for any equipment or operational problems.

The operator is around the equipment most of the shift and can easily recognize conditions as they change. Ask the operator if he or she has noticed anything unusual or abnormal with the operation of the press. Make notes in the comment section so a work request can be generated. 11.0 Check the burp cycle for correct operation.

The function of the burp cycle is to expel any entrapped air between the front section of the container and the die, preventing air bubbles and blisters forming in the extrusion. In order for the air to be pushed toward the front of the container, the cycle has to go through the upset cycle deforming the billet to the container wall, pushing the air to the front and back. Most of the air that is pushed to the back of the container (ram side) while the billet and dummy block are entering the container should escape around the dummy block unless there is excessive build up on the container liner or dummy block land or both. The operation of this cycle should be:

1. container closes and builds sealing pressure 2. main ram pushes the billet against die face building enough pressure to conform the billet to

the inside diameter of the container but not enough to extrude through the die 3. decompress the main ram pressure


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4. open the container, pushing the main ram back with the upset billet just enough to release the entrapped air

5. close the container and build sealing pressure This all should be done quickly with minimum shock. If the sequence is not correct, Refer to Sec. 2.0 on the Extrusion Press Troubleshooting Chart. 12.0 Check crosshead and container jamb nuts for looseness.

The container housing has adjustment studs for elevation alignment. Above the main top nuts, there are thinner nuts used to prevent the adjustment from changing during operation. Make sure these nuts are tight at all times. The same applies to the crosshead adjustment studs. 13.0 Check loader for proper operation and alignment.

The loader raises to receive the billet from the overhead loader and lowers to clear itself from the crosshead after the billet has safely traveled far enough into the container. The movements should be fast and smooth without shock or bounce. The loader contains a cradle for guiding the billet into the container. The cradle bars should be adjusted so that the back (ram side) is low enough to prevent interference of the float of the dummy block and high enough on the container side to prevent the billet from dragging on the edge of the container.

Top Of Press 14.0 Check motors and pumps for any unusual sounds or vibration while running. Become familiar with how the pumps and motors sound and react under normal, non-malfunctioning operation. Check every day for any abnormal sounds, vibration or heat build up from the press pumps and motors. Note in the comments section anything that is found so further investigation can be done. 15.0 Check press pit for hydraulic oil. Any hydraulic oil in the press pit should be pumped out. The hydraulic oil is combustible and can produce enough heat if ignited to destroy the press and endanger others. 16.0 Check and record the auxiliary pressure. Pump PF3 is used to supply hydraulic oil to move the rotostation die changer, loader and surge (pre-fill) valve and to assist the main ram travel during ram return. Check the setting of the relief valve by observing the pressure reading on the gauge. The pressure should be at least 500 but no more than 600 PSI. Record the pressure on the check sheet to verify proper system pressures. If the pressure is low, Refer to Sec. 8.0 on the Extrusion Press Troubleshooting Chart. 17.0 Check and record the pilot pressure. Pump PF3A is used to supply hydraulic oil to shift the larger spool valves in the system and to provide pressure to hold up the butt shear. Check the setting of the relief valve by observing the pressure reading on the gauge when this pump is loaded. The pressure should be at least 150 PSI. Record the pressure on the check sheet to verify proper system pressures. If the pressure is low, Refer to Sec. 8.0 on the Extrusion Press Troubleshooting Chart. 18.0 Check and record the servo pressure. Pump PF4A is used for one function only. It is used to supply hydraulic oil to the main pump servo valves for controlling the stroke of the main pumps. Check the setting of the relief valve by observing the pressure reading on the gauge. The pressure should be at least 500 PSI and no more than 600 PSI. Record the pressure setting on the check sheet to verify proper system pressures. If the pressure is low or if the pressure has extreme swings when the pumps stroke, Refer to Sec. 8.0 on the Extrusion Press Troubleshooting Chart.

by David Turnipseed Date 03/29/04, Ver. 1.3


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Extrusion Press Troubleshooting Chart Item Problem Causes Possible Solutions 1.0 Butt Shear Operation 1.1 Improper butt shear cut Excessive clearance

between blade and die face

Check clearance with a feeler gauge between blade and hot tool stack. The clearance should be between .005 and .010 (0.12 - 2.5 mm)

Loose bolts Check to make sure the butt shear blade bolts are tight.

Excess clearance between tool stack and die slide/carrier saddle ring.

Check for wear on retaining ring. Repair or replace.

Check for excessive wear on die slide wear plates. Replace.

Check for worn or damaged cutting surface on blade. Replace if necessary.

1.2 Butt shear blade reaches the butt and will not cut

No assistance from main pumps.

Check to make sure all pumps are on and operating. See note 1

The hydraulic circuit of the shear is still in the regeneration cycle

Check the limit switch for changing the circuit from speed to power for improper position. See Note 2.

1.3 Butt shear slams on return stroke

Return slow limit switch not working properly

Adjust limit switch position

Cylinder cushion not working

Adjust cylinder dampening screw.

1.4 Butt sticks to blade and won't release.

Lubrication equipment not working properly.

Check to make sure system is spraying lubricant on the blade. See Note 3.

Excessive aluminum build up on blade

Change blade

Butt knocker not functioning properly

Check air pressure setting

Check mounting bolts for looseness

1.5 Butt knocker not extending

Incorrect air pressure Check air pressure at directional valve for proper pressure

Loose mounting bolts, binding

Tighten, Replace if missing

Bent knocker rod Replace knocker rod.

1.6 Butt shear lifts tool stack on return stroke.

Missing or damaged hold down bar

Repair or replace. See Note 6

1.7 The die or tool stack rotates during the shear cycle

Missing key stock Replace key stock


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Extrusion Press Troubleshooting Chart 2.0 Container Operation 2.1 Container will not close Interference from butt

shear Check to make sure butt shear is in the full up position and the butt shear up limit switch is made.

Tilt Switch Check to make sure the container is not tilting off the tilt limit switch

2.2 Container will not open Program out of sequence

Check program logic

At the end of the extrusion cycle with a weld pocket or feeder plate die the butt length may be to long

Continue extrusion if possible to the maximum butt length.

2.3 Container moves side to side when closing or opening

Excessive clearance at the container guide

Adjust or replace rear plates if there is no adjustment

Excessive clearance between shifting cylinder nuts and container housing.

Adjust to proper clearance and correct distance between front nuts and platen.

2.4 Container slams against die face

Pump controls need calibration

Check calibration between pump stroke command and pump stroke position feedback position

Oil temperature high (Low oil viscosity)

Check cooling system for proper operation

Check for excessive heat build up in hydraulic system

Limit switch or position sensor problem

Check slow down limit switch for looseness of switch or switch arm or position transducer.

2.5 Burp cycle does not initiate.

Burp cycle selector in off position

Switch selector switch to on position

Burp cycle selected for no burp on first billet

This is OK unless die is already filled with aluminum

2.6 Burp cycle initiate but container never actually moves.

Shifting cylinder nuts have too much clearance

Set shifting cylinder nuts to proper clearance between face of nut and container housing. See Container Alignment Procedure.

Container limit switch position

Adjust container closed limit switch for proper operation.

Container open timer Timer open preset value may be too low for oil temperature.

Oil temperature low Check cooling system for proper operation


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Extrusion Press Troubleshooting Chart 2.7 Container opens too

much during the burp cycle

Oil temperature high Check cooling system for proper operation

Container open timer Timer open preset value may be too high for oil temperature.

2.8 During strip cycle the container and ram move at the same time.

Ram return limit switch making prematurely

Adjust limit switch arm.

Ram position transducer feedback signal incorrect

Calibrate sensor.

2.9 The container closes but does have any sealing pressure

Container closed limit switch is not made

Check container closed limit switch for proper operation

Sealing pump not in operation

Check and make sure sealing pump is turned on and operating

Sealing pump load valve not functioning

Check to make sure the load valve is energized and has shifted

Container tilted Check for build up on the bottom of the face of the container liner or the die or die ring.

2.10 The container closes and builds pressure but is low

Pressure does not build at pump with pump running

Check pump compensator for proper adjustment - See pump operation manual for adjustment procedure.

Check backup relief valve for internal leakage

Check shifting cylinders for leakage around cylinder pistons. See Note 4:

2.11 The container builds pressure after the ram builds pressure

Container closed limit switch out of adjustment

Change the position at which the switch makes during container close. See Note 5

System leakage is high Find source of leakage and repair

3.0 Billet Loader Operation

3.1 Billet loader will not raise

Ram position not in safe position

Check main ram position for clear; Check ram position for proper feed back position

Hydraulic control problem

Check hydraulic auxiliary circuit for proper pressure

3.1 Billet loader has jerky motion

Hydraulic control problem

Check hydraulic circuit feeding loader for proper pressure

Mechanical looseness Check loader pivot bushing for excessive wear. Replace if necessary.


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Extrusion Press Troubleshooting Chart 4.0 Main Ram 4.1 Main ram will not

advance Die slide position Check to make sure the die slide in a

safe position and the slide position limit switch is made.

Loader check position Check to make sure loader is in the clear position

Butt shear position Make sure the butt shear is in the up position and the limit switch is made

4.2 Main ram will not return Press sequence is out of cycle

Check program logic

4.3 Main Ram Advancing Slow



Press cycle out of sequence

Check program for improper conditions.

4.4 Stem/Dummy Block Loading

Container/Ram Alignment

Check container to stem alignment. Adjust if necessary.

Build up on entrance of container

Check for proper loader to stem/container alignment.

4.5 Main Ram slamming on return stroke

Ram position transducer feedback signal incorrect

Calibrate sensor.

Incorrect pump stroke command

Check program for correct preset value

4.6 Main Ram retracts at the same time the container opens after the end of the extrusion cycle.

Butt stripped limit switch making prematurely

Adjust limit switch position

Container open speed higher than ram return speed

Look for cause of slow ram return speed.

5.0 Extrusion Cycle 5.1 Maximum extrusion

pressure cannot be reached

System Relief valve by passing

Check for contamination in valve or worn parts. Clean or replace if needed

Check for proper pressure setting. Adjust if necessary.

5.2 Maximum extrusion pressure is too high

Pressure transducer incorrect

Check calibration of system electronic pressure transducer. See System Pressure Transducer Calibration.




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Extrusion Press Troubleshooting Chart 5.3 Preset extrusion speed

cannot be reached Pump controls need calibration


Pumps not on line Check to make sure all pumps are on and operating.

Internal leakage Check hydraulic system for heat build up to find leakage.

5.4 Runaway extrusion speed

Ram position transducer feedback incorrect

Check for missing speed signal

Loss of main pump stroke feed back signal

Check for feedback signal at pump amplifier card.

5.5 Shock at the end of the extrusion cycle

Decompression of cylinder too fast

If adjustable, decrease. If not, ramp speed down at the end of the extrusion cycle

5.6 Loud noise around the pre-fill valve at the end of the extrusion cycle

Prefill valve opening too soon

Check program for correct pressure setting.

Check pressure transducer for proper feedback.

Check dampening controls on prefill valve for proper adjustment.

5.7 Ram slams into billet when loading

Ram position transducer feedback incorrect

Check calibration of ram position transducer. See Ram Position Calibration Procedure.

5.8 Incorrect butt size Ram position transducer feedback incorrect

Check calibration of ram position transducer. See Ram Position Calibration Procedure.

6.0 Die Change Cycle 6.1 Auto die change cycle

will not initiate Process out of sequence

Check conditions in program

6.2 Die slide will not move Main ram not at safe position

Check the position of main ram: Check position feedback

7.0 Pumps and Motors 7.1 Main pump motors will

not start Auxiliary pump off Start auxiliary pump first

E-Stop engaged Locate the E-Stop that has the control circuit locked out

Motor overload tripped Investigate overload cause and reset

Main line fuses blown Investigate over-current cause then replace fuses

Disconnect off Investigate reason (Should be locked out if off)


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Extrusion Press Troubleshooting Chart 7.2 Main pumps will not

stroke No servo pressure from auxiliary pump

Check pressure at servo relief valve

No command from amplifier card to servo valve

See Servo System Troubleshooting Chart

Flow control valves to servo valves shut off

Turn on

7.3 Main pumps stroke slow

Oil flow restriction to servo system

See Servo System Troubleshooting Chart

Low servo pressure from auxiliary pump (PF4A)

Check pressure at servo relief valve

7.4 Pumps stroke but can not build pressure

Load valve Z1 or Z2 not energized

Check program for conditions.

8.0 Auxiliary Pumps 8.1 Motor for auxiliary

pump will not start E-Stop engaged Locate the E-Stop that has the control

circuit locked out

Hydraulic oil high temperature switch made

Refer to Section 9.0

Motor overload tripped Investigate overload cause and reset

Main line fuses blown Investigate over-current cause then replace fuses

Disconnect off Investigate reason (Should be locked out if off)

8.2 Auxiliary pump (PF4A) has low pressure

Relief valve bypassing Clean or repair valve

No volume from pump Repair or replace pump

8.3 Auxiliary pump (PF3A) has low pressure



8.4 Auxiliary pump (PF3) has low pressure



9.0 Cooling System 9.1 System hydraulic oil

temperature is high No oil flow through heat exchanger

Pump (PF4) is bad. Repair or replace

Heat exchanger is clogged on water side. Check pressure in and pressure out. Clean if high differential pressure.

No water flow through heat exchanger

Check water pump from cooling tower.

Heat exchanger is clogged on water side. Check pressure in and pressure out. Clean if high differential pressure and temperature.

Excess heat generation in hydraulic system

Check for areas of high heat around cylinder pistons and relief valves.


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Extrusion Press Troubleshooting Chart 9.1 System hydraulic oil

temperature is low while running

Too much water flow Decrease water flow

Note 1: If the butt shear cylinder is enabled to stroke down and no oil is supplied, the shear will drop to the butt from its own weight and no cutting will occur. Note 2: If the shear blade comes in contact with the butt before the limit switch makes, no power is available for cutting. Note 3: Never allow the butt shear lubricant to be applied when the container is open to avoid contamination on the face of the die and inside the container liner. Note 4: Check temperature of the cap end of the cylinder vs. the rod end. If oil is blowing by the piston rings at high pressure there will be considerable heat difference. Note 5: The sealing pump is a very low volume high pressure pump. The container must be closed with the main pumps so that the cylinders are completely filled with oil so the sealing pump only has to pressurize the cylinders. Note 6: The hold down bar should not allow the tool stack to be lifted up more than the height of the key that extends into the bottom key way of the tool stack.


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The next pages offer some helpful recommendations by Mr. P. Gopalan Kutty an experienced Extrusion Maintenance Manager. We hope readers will find these recommendations useful and will likewise share their ideas and experiences for future editions of this Manual.

The Voice of ExperienceThe Voice of ExperienceThe Voice of ExperienceThe Voice of Experience

Extrusion Press - Maintenance A Predictive Approach The Aluminum Extrusion industry is a fast developing industry, and as a result the whole approach to performance and maintenance is also changing. Gone are the days when one was happy with a 15 second dead cycle and a 5% breakdown percentage. The modern presses with high-tech hydraulics and PLCs are capable of running at 10 seconds and consume a lot less energy and manpower. Front loading, short stroke, longer billet lengths, double pullers and longer run out all contribute to better performance and recovery. In earlier days, a good lubrication program, periodic alignment checks, routine check on wear parts and a good filtration system were the foundations for a maintenance program. With the development of PLC controls the first big steps in improvement started. Not only did they eliminate all moving electrical contacts but they also shaved seconds from each operation. This resulted in the need for better hydraulic components with proportional controls that complemented the PLC controls. With the advent of modern hydraulics the need to keep the oil cleaner became all too obvious. So, extrusion as a whole evolved to a faster, more efficient and high tech operation. The advent of management information systems interfacing with PLCs opened a whole new world in performance analysis. Where does that leave a maintenance man, and what options does he have available to do his job better? What are the new tools available for a maintenance professional? Tools of the past:

Manual Lubrication Torque and tightness checks Ultrasonic inspections Alignment checks using optical telescope (transit) Weld inspections Hydraulic oil analysis

Tools of the present: Sensors to monitor wear, alignment, central lubrication Encoders to measure accuracy Wear indicators and position indicators Infrared thermography Particle counting and oil purity

Tools of the future:

Wireless monitoring Internet

The terms predictive and proactive are used widely, but how does one find modern tools to justify them? Prediction is always based on past performance and parameters against the present ones to indicate future trends. Structural Inspections. Even though hydraulics and controls and certain innovative designs have changed over the years, the heart of an extrusion press is still a sound mechanical structure. A time-based program for crack detection by magnetic particle or ultrasonic flaw detection techniques on


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major welds will give you an indication of the soundness of press components such as columns, main cylinder and container. Alignment Checks. A periodic alignment check on the press will give an indication of wear and tear on bushings and other moving parts. Information Technology. This is one area where things have changed by leaps and bounds. Management information systems and Process information systems play an integral part in maintenance. Management information systems are real time material tracking and data acquisition systems which help the maintenance staff not only to monitor but to take critical decisions on important equipment. Process information and control systems are man-machine interfaces that enable the operator to monitor and optimize the production and to quickly find the error causes or malfunctions. They show:

current machine data status data for the maintenance staff display and print out of alarm and alarm history diagnostic text all production input data

Both of these applications track material and machine status in real time in a Windows-based application. Every aspect of the Extrusion operation from Die to Dummy block dimensions is recorded and tracked. From the Maintenance point of view, graphic representation of the performance of pumps, container heating, oil temperature and pressure will give a true indication of the performance of the components. Predictive maintenance depends a lot on performance characteristics and the features help in planning a maintenance activity on major press controls. Since it is linked to the PLC the alarm history analysis and status history are two other tools for Maintenance personnel.

Using Wireless Technology and the Internet for Predictive Maintenance

Wireless, Point-to-Point Communication System. The wireless ethernet link between a monitoring system on an industrial machine can transmit data to an end user PC. This opens a whole world of Maintenance possibilities. For example, vibration sensors send the data and the end user can monitor them as real time gauges. The success of the future Maintenance Department will depend a lot on their ability to use these modern tools for monitoring and thus predicting failures well in advance.

The Millennium Maintenance Team A good Maintenance team will need employees with a balanced blend of electrical, electronic, PLC and computer skills. The Engineer or Maintenance technician can not only monitor but even predict failure of the system or components from a far away place. So the approach to maintenance is changing and to survive one needs to be able to process the huge data available and to make use of them as a tool for maintenance.


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EXTRUSION PRESSES: Routine Inspection of Major Structural Components 1. Columns

a. It is recommended that approximately once each month a check be made to ensure that all column nuts are tight and there is no undue movement when under load. It is most important that the nuts have uniform tightness; otherwise the columns will carry uneven loads.

b. It is recommended that the columns be ultrasonically examined at least once every 12 months to ensure that no internal defects exist. Particular attention should be paid to the area adjacent to the threaded portion at the ends of the column. It is advisable that the ultrasonic examination be made when the columns are loaded, since this gives greater accuracy in recording slight changes in condition.

c. Should the ultrasonic examination reveal any defective areas, the frequency of examination should be increased so that changes in the defect size can be monitored. It is recommended whenever a defect is located in a column, immediate consideration should be given to replacement. Decision on the speed of replacement must take account of the size and growth rate of the defect.

2. Welded Main Cylinder a. It is recommended at intervals not exceeding 6 months, an inspection be made of the welds

connecting the housing plates to the cylinder body. Particular attention should be given to the circumferential weld nearest to the filling valve end.

b. The recommended method of testing is the magnetic particle technique: many press users prefer the dye-penetrant method, but this is sometimes difficult to interpret if the weld profile is not smooth.

c. The type of defect most likely to be exposed by a routine inspection procedure is a small crack in the main cylinder body immediately adjacent to the weld metal. If such a defect is discovered, this should be ground out immediately to remove all of the defect. It is strongly recommended the repair procedure be discussed and agreed with the press manufacturer if possible.

Optical Alignment of the Extrusion Press Prior to optical alignment it is advisable, in order to ensure a speedy return to normal production, to carry out the following procedure:

1. Switch off container heating immediately after production ceases, leaving the container in the fully unsealed position. If possible arrange an air blast to expedite cooling.

2. Remove all tooling, i.e., dies, bolsters, pressure pads and thrust rod. 3. If the container is to be aligned, ensure that the bore is clean and smooth ready to accept a

target holder. 4. Remove the lead-out table, quenching system or other handling equipment directly attached

to the front platen housing to enable the telescope to be mounted on the outside of the platen.

5. Fix the illuminated target holder and target on the stem holder with an adaptor. 6. Take an initial reading at the start of the travel. 7. Take the second reading at the middle of the travel. 8. Take the final reading at the end of the travel. 9. Note the deviation or dip of the main ram. 10. Allowed dip is 0.012 or 1/1000 of a foot for a 16 MN 3-column press.


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Preventive Maintenance - a More Sophisticated Look To set a PM program in motion is not very difficult but to measure its effectiveness is more difficult. If after doing routine preventive maintenance you still notice that your press is delivering a low performance in terms of dead cycle, then it is time to sit up and do something about it. The term optimization is significant and should be incorporated in the press maintenance schedule on a periodic time interval of at least once in two years or depending on the performance. Performance Optimization. PO is of high value and is based on the periodical measurement of press dead cycle. The first indication of a press having a problem is usually obtained from the dead cycle time. If one notices a significant change then the problem comes in finding out from where exactly this is originating, and this can be done by a dead cycle analysis. A list press of operations depending on the particular design of press is tabulated the time for each operation is noted.

TIME Pressure release Stripping Ram backward Container open Shear Down Shear up Container close Loader in Ram forward Loader out Upsetting Release Container open Container close Upset

After recording these times for each part of the cycle, dead time is calculated as is and compared to the value when the press was first commissioned. If there is a set of readings available from the time of the last tuning or commissioning then the task of the PM tuning team becomes easier. Once the operation cycle is plotted an idea of time lapse can be identified. A hydraulic circuit diagram with a valve sequence chart is used for further identifying the defect. The circuit usually indicates the speed and the cross sectional area of each cylinder. Before going for sophisticated measuring instruments one can use the ram movement indicator on the press by following this simple procedure:

Select a particular operation, for example Main ram backward. From the valve sequence chart identify the particular valve or valves in operation. Identify the pump and the percentage of delivery for this operation. Note down the designed pump delivery. Mark out a particular length on the ram movement. Time the distance marked.

Example: Let us say for a main ram backward operation you need pump number one delivering one hundred percent to obtain a speed of 28 mm /sec. The actual measurement indicated the speed as 24mm/sec and this shows that either the pump is not delivering the required oil for that operation or hydraulics are at fault.


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By applying the formula Q = A x V where Q is the quantity of oil (in this case the actual pump output), A the area of the cross section of the ram from the hydraulic circuit and V the measured speed, the pump performance can be obtained. By comparing this to the designed output the actual performance of the pump is evaluated. Most of the pumps have indicators for the degree of operation, from which one can come to a conclusion about the pump delivery status. From this data it is possible to conclude that either the pump is not delivering the required quantity of oil for the operation or there is something wrong with the related valves. This is just to give an idea about the methodology and there are many providers who specialize in fine tuning the press. A lot can be done with effort and innovation before calling the experts.

Thermal Alignment. Mechanical alignment of the press is something everyone knows and does on a periodic cycle, but the term thermal alignment is a new term which few of the extruders carry out to improve their productivity, die life and quality. The process of monitoring and controlling the thermal conditions of the profile, billet, die and container can be defined as thermal alignment. Basically isothermal extrusion can succeed only if you have the proper control of these factors. Single cell die ovens, multi-zone heating in containers, highly accurate taper heating of billets, and provisions to measure the exact temperature of the billet before feeding to the press, either by thermocouples or non-contact pyrometers, are all important to achieve this thermal alignment. Exit temperature directly affects the extrusion speed, and any variation in any of these factors will decrease the extrusion speed and any advantage of isothermal extrusion will be lost.

Older Aluminum Extrusion Presses - a Second Chance? When do you declare a press as old? Is it when you see: Leaking hydraulics and components? Out-dated energy guzzling pumps? Relay logic and loose dummy blocks? Weld scars on the main housing? A dead cycle of thirty seconds? Is the old veteran ready to say a sad good bye? Some cry that it is high time you dump it to the scrap heap, or is there something one can do upgrade it? Over the years one often hears this comment among extruders. The question here is: Is it possible to extract more out of an aging press? Is it possible to modernize it? The answer to the question can be very tricky. If you say Yes and No then you are like a good politician. But this is Engineering and not politics and one should be able to give a positive reply. The purpose of this paper is to explore the possibilities and pit falls in modernizing. Aluminum extrusion presses over the years have evolved dramatically. Gone are the days when you were happy with a fifteen second dead cycle time and a break down time of 5 percent. Engineering designs and modifications rest on four main pillars:

Engineering economics Actual engineering itself Management commitment People psychology

Engineering Economics. Simply put it means whether the benefit is worth the expense. Many projects are undertaken without going deeply into the aftermath of the new addition or modification. A case example here is that of a standard Extrusion press with a shearing problem. The introduction of a modern shear with butt knocker was very attractive and effective. Unfortunately the added thickness of the shear housing to accommodate the butt knocker was not taken into account. As a result the container position and hence the billet length had to be modified. This resulted in a


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reduction of the billet by 20 mm and one can imagine the substantial loss in production over the years. This is just to stress the need to conduct a deep study before venturing forth into the world of modernization. Venders flaunt brilliant performance of their systems but one needs to study not only the performance of the press but the related ancillary equipment, too. The initial study should start from the types of profiles and the economical billet length and run out. These to a large extent improve the recovery. The best way is to make a check list with all the positive and negative aspects of modernizing. Let us start with the Press itself. What are the possibilities and what are the criteria required? A sound Mechanical structure is important. One needs to look at the heart of the mechanical structure: columns, main housing, platen and end housing, condition of the cylinders. If any of the above shows either wear or even small cracks or damage, the possibility of either replacing or repairing must be taken into account. Once you have the basic sound mechanical structure the next step is to assess the present condition of pumps, hydraulics and controls. All these can be upgraded for better performance but a study will throw light to the nature of challenge one is in for. While doing this it is good to look into the existing documentation and circuits. As is often the case with many presses, when some kind of modification or addition takes place, few take the trouble to upgrade the documentation accordingly. A look at the existing inventory is recommended to know if there are any major parts lying in stock over the years and the present stock value. It is essential that a flow/performance diagram of the performance of the press is mapped to get a clear vision of the performance of various press components. The next logical step is to investigate the likelihood of bottle necks that can limit the press output even if its performance is upgraded. A billet heater that fails to deliver on time, a puller that has a longer dead time, length of the run out, all come into focus here. Even with poor performing or outdated ancillary equipment one has the possibility of getting better output from an older press. In such cases the 40% rule of thumb will be of help. If the cost of modification falls below 40% of a new one, the prospect of getting much better return of investment is very bright indeed. Conclusion The best method is to evaluate older presses, and most of them have the potential to improve their performance substantially with the right approach. Once the decision is made, there are many Engineering service providers who can design an efficient system tailor-made to suit based on client need. So it is always advisable to explore all avenues before condemning a press to the scrap heap.

Written by: P. Gopalan Kutty Maintenance Manager, Gulf Extrusions, Dubai


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Editors Note: The following information is taken from a Farrel training course manual, circa 1968. The training course was offered to all new owners of Farrel extrusion presses. This information is both interesting and useful, for users of older as well as modern presses, for Farrel and other makes.

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Press Installation I. Preparation of the Site

Consideration should be taken when locating a press in your plant. The press should be positioned

Date post:	25-Nov-2015
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